Electric furnace electrode holder



g- 1, 1933- A. E. GREENE 1,920,378

smic'mm' FURNACE ELECTRODE HOLDER Filed July 16. 1931 2 Sheets-Sheet 1 & INENTOR ATTORNEYS Aux-1,1933 A. E. GREEN: 7' 1,920,378

ELECTRIC FURNACE ELECTRODE HOLDER Filed July 16. 1931 2 Sheets-Sheet 2 INVE'NTOR v 'ATTORNEZS Patented Aug. l, 1933 PATENT OFFICE ELECTRIC FURNACE ELECTRODE HOLDER Albert E. Greene, Medina, Wash. Application July 16, 1931. Serial No. 51,181

3 Claims.

My present invention relates to electric furnace electrode holders and to electrode contacts for conducting current to the electrode.

My present application is a continuation in 5 part of my application for patent Serial No.

. 527,102 filed April 2, 1931.

Electrode holders and contacts on electric furnaces are often subjected to extremely hot gases and flames which at times come from the furnace chamber beneath. Due to expansion and contraction and to oxidation from the heat, bolted jointsor connections between the electrical conductor which brings the current to the electrode contactand the contact proper often deteriorate and cause loss of power and damage to the contact proper. The high temperature to which this connection is usually subjected is such as to ordinarily prevent use of common solder. In my previous electrode holder and contact designs I' have used a contact with a hole into which the conductor cable is brazed. The temperature is not suflicient to affect this brazed joint. I have found, however, that a simpler and more eflicient joint between cable and contact can be made in accordance with my improved construction. This improved construction comprises a contact having a water-cooled cable lug integral with it and into the hole of which the cable end is bolted. By water-cooling this contact surface I am able to use a cable end having a pipe member around the end of the cable and to use a soldered joint to make a better connection between the end wires of the cable and the surrounding shortv length of pipe, which pipe, in turn fits snugly into the contact lug holewhere it is held in place by means of bolts. My improved construction avoids the usual trouble with bolted joints because this joint is water-cooled. The contact member proper comprises a surface which abuts the electrode and a water cavity directly back of this surface for cooling this part of the circuit, and the contact member also has the integral, water-cooled cable lug, thus avoiding bolted joints which are not cooled.

In conducting very large currents such as currents of from 10,000 to 25,000 amperes'to an electrode of the usual type, copper pipe conductors have been used to carry the current to a stationary member mounted at the end of an electrode arm and by means of water circulation within the copper pipe it is possible to carry currents of large amperage without nearly so much copper because the heat thus formed can be carried away. One objection to such construction is the necessity of further conducting the current from the stationary element mounted on the end of the arm to the adjustable contact members which are pressed against the electrode. Additional joints are necessary between the memher on the arm end and the movable contact (CI. 13-16) I members. Such construction does not lend itself er combination comprising two hinged contact clamps each mounted on a clamp hinge and each carrying a conducting contact member which contact member is fitted with an integral lug for the end of a copper pipe conductor through which water can circulate. The contact is also provided with a water cavity to cool the surface of contact with the electrode. My improved construction comprises a sufficiently long pipe conductor so that ample flexibility is provided in the pipe to permit of the slight movement of the lug portion of the contact when the electrode holder is opened and closed. Opening and closing of the contact clamp is necessary when the electrode is lowered through the holder and contacts, for example, as a result of wear. In my. improved construction I prefer to locate the integral pipe lug at the part of the 'contact member where the movement is least, that is,as near the hinge pin as is convenient. It will be noted that the movement at this location is very much less than at the clamp bolt. location on the farther side of the electrode from the hinge pin.

The invention will be better understood from aconsiderationof the following description in conjunction with the accompanying drawings in which Fig. 1 is a plan of an electrode holder end assembly embodying my invention and adapted more particularly for use with smaller diameter electrodes such as those of 8 inches diameter or less;

Fig. 2 is a side elevation showing the contact member and electrode of Fig. 1 and showing the water pipe connections but with the clamping members not shown;

Fig. 3 is arear elevation of the side of the holder toward the mast, showing both the contacts shown in Fig. 1, illustrating the water connections and showing the integral cable lugs;

Fig. 4 is a side elevation of the assembly shown in Fig. 1 with the clamping member and hinge clamp in position;

Fig. 5 is a plan of anelectrode holder assembly for relatively large electrodes, comprising two contacts and a pipe conductor leading directly to each contact thus providing a single joint between conductcr and contact and means for cooling this pipe joint by water circulation in the pipe itself; and,

Fig. 6 is an elevation of the assembly shown in Fig. 5. a

Referring first to the holder combination shown in Figs. 1 to 4, inclusive, the electrode 1 is held between two contacts 2 and 3. The contacts 2 and 3 are held within clamp members 4 and 5 which are hingedly mounted on pins and on hinge bracket members 6 and 7. The hinge members 6 and '7 are mounted on the end of the electrode arm pipe 8 with insulation between them and the pipe arm. The insulation is shown at 9 and it covers the sides and top and bottom of the arm end which is rectangular and attached to the pipe section of the arm 8. The hinge members have slotted holes for the bolts 10 and thus provide for lateral adjustment, as more particularly described in my above-mentioned co-pending application.

The contact member 2 is shown in Fig. 2 and both contacts in Fig. 3 with the clamps removed. The contact member 2 is provided with a cooling cavity 11 which serves to cool the electrode contact surface and it also has a water cavity 13 adjacent the cable lug for cooling the surface of the contact here,indicated at 14. A water pipe 15, preferably of copper, enters the cooling cavity 13, and another pipe 16 carries the cooling Water from this cavity to the cavity 11 and thence through the pipe 17 the water can pass to the opposite contact member. These water pipes are connected through insulating hose sections on the electrode arms to the source of water and short circuits are thus avoided.

A conductor cable, preferably of copper, is shown at 19 and another at 20. These cables terminate in short sections of copper pipe indicated at 21 into which they may be soldered or sweated. These pipe ends extend into and through the integral lugs and make a tight fitting contact with the inside surface 14 of the lug. The water from the pipe 15 passes through the opposite contact and out the pipe 18, and both contact lugs are thus cooled. The integral conductor lug 12 has the hole through it bored to make a good contact surface 14. The cable end pipes are held tightly within these holes by means of bolts 22 and 23. The electrode clamping mechanism is shown in Fig. 1 at 25. The screw member 24 fits in an adjustable nut member 26 mounted in the clamp 4. The hinge pin is shown at 26. The water cavities have their entrance holes preferably threaded to receive standard copper pipe fittings and thus together with the lug bolts provide for quick change of cables or for insertion of contacts of a different size without loss of time or material.

Figs. 5 and 6 show electrode holder assembly suitable for large electrodes and for large current capacity, and at the same time embodying the essentials of my already described contact members having integral water cooled conductor lugs. This modification of my invention provides a copper pipe conductor flexibly mounted on the holder and terminating in the integral lug of the contact which lug is cooled by the circulating water within the conductor pipe. Another such pipe is provided for the opposite contact. These pipe conductors are indicated at 36 and 37 entering the integral lug parts 35 and 38, respectively, where they are held tightly by means of the bolts which squeeze the sides of the lug against the pipe. The electrode 41 is held between two adjustable clamp members 32 and 33 with the contacts 30 and 31 between and against the electrode. The lug 35 is preferably a part of the contact casting although it could be made integral therewith in other ways such asby welding. The contact 30 is provided with a water cavity 45 for cooling the main electrode contact surface and another cooling cavity 43 for cooling the upper part and lug portion of the contact. Water circulates from the end of the conductor pipe 37 through the small circulating pipe 42 into the upper cavity 43 and thence through the pipe 44 into the cavity 45 and thence out through the pipe 46 tothe other side of the electrode through corresponding cavities and out the other conductor pipe 3'7.

The contact 30 held within the clamp 32 can be screwed to the clampby a small bolt 49 so that when the clamping mechanism indicated at 34 is opened or closed the contact follows the clamp and thuspermits quick dropping of the electrode. The clamps are held, each on a separate hinge member by pins as at 39. These hinge members are preferably fitted with slotted holes for longitudinal adjustment and for lateral adjustment of the electrode position. The insulation is indicated at 48.

An important feature of this combination is that which provides flexibility of the contact Without loosening the lug joint which holds the pipe end in the lug 35. The copper pipes are mounted within suitable insulation (not-shown) at the. mast end of the electrode holder and they provide ample flexibility to allow for the small movement of the lug portion. Thus, a move ment of 4 inch at the outer end of the clamps to increase the opening between them results in a movement of less than of an inch at the lug contact. Furthermore, in case of a change in electrode position the copper conductor pipes may be readily moved slightly to or from the electrode through the insulated supports on the electrode holder (not shown), or, in case of a change of contacts to substitute a different sized electrode, the change can be made merely by loosening the lug bolts and the circulating pipe fittings.

It is understood that the conductor lugs integral with the contact members can be made for two or more conductors, either pipe conductors or cable conductors. It is also understood that the cable can be clamped directly into the integral lug without the cable end pipe described, and in the case of cables, the integral lugs may have the water cavities located in other positions so long as cooling is. accomplished. It is believed that the improvements embodied in these modifications of my present invention result in a great saving and convenience compared with any heretofore used and they result in longer life of parts and less 'loss of-energy in heating through poor contacts.

What I claim is:

1. An electrode contact element comprising a water-cooled contact portion, and an integral lug having a recess for the reception of a conductor and having a separate passage for cooling fluid in the lug adjacent the conductor surface.

2. An electrode contact element comprising a contact portion provided with a water-cooling cavity, and an integral lug having a recess for the reception of a conductor and provided with a separate water-cooling cavity in the lug forcooling the conductor contact surface.

3. An electrode contact element comprising a contact portion provided with a water-cooling cavity, an integral lug having a recess for the reception of a conductor and provided with a separate water-cooling cavity adjacent the conductor contact surface, and a tube connecting the cavities to permit the circulation of water therethrough. ALBERT E. GREENE. 

